TODO XSH2:

- ls --no-out  ... return the serialization rather than printing it

- split [after|before] ...
- split text on a given character???

- more tests
- support DTD modification (isn't that obsolete in the 21st century?)

- add various examples of working with namespaces, e.g.

	if the ttt prefix is aready declared in the context of . or
	registered, one may simply do

		add element ttt:para into . 

	and the new element ttt:para will be bound to that namespace so
	doing

		ls //ttt:para;
		ls//*[local-name()='ttt' and
		      namespace-uri()='http://myuri.com'];

	should both list it.

	       add --namespace http://myuri.com element "ttt:para" into .

	is intended for adding a new element together with a
	xmlns declaration of its prefix and the given namespace.

INFO COMMANDS AS XML:

xsh$ ls &{doc-info --xml}
<doc-info>
  <version>1.0</version>
  <encoding>utf-8</encoding>
  <standalone>-1</standalone>
  <compression>-1</compression>
  <URI>sample/sample5.a.gz</URI>
</doc-info>

and the same for more info commands

USER-LEVEL IMPLEMENTABLE

- reload document
- untag/split element                
- comment-out node (?? uncomment ??) 
- swap nodes command or more generally, reorder {[2,1,3,4]} //foo
  currently doable either with a sort:
    $neword = {my $i=0; { map { $i => $_ } (2,1,3,4)} };
    xmove &{ sort :k {$neword{position()}} //foo } replace //foo;
  or, even simpler way, using variables:
    $match = //foo;
    move { @$match[1,0,2,3] } replace //foo;
